Rh–POP Pincer Xantphos Complexes for C–S and C–H Activation. Implications for Carbothiolation Catalysis

The neutral Rh(I)–Xantphos complex [Rh(κ3-P,O,P-Xantphos)Cl]n, 4, and cationic Rh(III) [Rh(κ3-P,O,P-Xantphos)(H)2][BArF4], 2a, and [Rh(κ3-P,O,P-Xantphos-3,5-C6H3(CF3)2)(H)2][BArF4], 2b, are described [ArF = 3,5-(CF3)2C6H3; Xantphos = 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene; Xantphos-3,5-C6H3(CF3)2 = 9,9-dimethylxanthene-4,5-bis(bis(3,5-bis(trifluoromethyl)phenyl)phosphine]. A solid-state structure of 2b isolated from C6H5Cl solution shows a κ1-chlorobenzene adduct, [Rh(κ3-P,O,P-Xantphos-3,5-C6H3(CF3)2)(H)2(κ1-ClC6H5)][BArF4], 3. Addition of H2 to 4 affords, crystallographically characterized, [Rh(κ3-P,O,P-Xantphos)(H)2Cl], 5. Addition of diphenyl acetylene to 2a results in the formation of the C–H activated metallacyclopentadiene [Rh(κ3-P,O,P-Xantphos)(ClCH2Cl)(σ,σ-(C6H4)C(H)═CPh)][BArF4], 7, a rare example of a crystallographically characterized Rh–dichloromethane complex, alongside the Rh(I) complex mer-[Rh(κ3-P,O,P-Xantphos)(η2-PhCCPh)][BArF4], 6. Halide abstraction from [Rh(κ3-P,O,P-Xantphos)C...